Which CSP specializes in SST? How the six certified providers are built

Short answer: none of the six is an SST-only company, and the certified services are the same at all of them. What differs is scope and segment. For TaxCloud and AccurateTax, United States sales tax is the whole business, TaxCloud for mid-market brands and AccurateTax for small business. For Avalara, Sovos, and Avior, SST sits inside a portfolio spanning global VAT, e-invoicing, or excise verticals. Exactor is inside QuickBooks.

There’s no clean answer to which provider specializes in SST, and the program is the reason. The Streamlined Sales and Use Tax Agreement, as amended through May 20, 2025, defines a Certified Service Provider as an agent certified to perform your sales and use tax functions, other than the tax you owe on your own purchases. That definition is identical for all six. The question you can answer is structural: what is SST to each of these companies? That is observable from each company’s own published scope, and nothing here goes beyond it.

What’s identical across all six

Before anything differs, the program fixes three things:

• The certified free services list is the same. The Governing Board sets it: system setup and integration, tax calculation, return preparation and filing, remittance, notice and audit response, and data privacy protection.
• The compensation model is the same. In the Board’s words, “the CSP should not charge a seller for the CSP services for any Streamlined member state in which the seller meets the definition of ‘CSP-compensated seller.’” That’s a program rule, not a vendor offer.
• Qualification is yours, not the provider’s. Whether you qualify is decided per state, against all five criteria in the CSP Operating Contract. See the CSP-compensated seller test.

So a provider can’t be more or less certified, and it can’t sell you a bigger version of the free services. Everything a provider differentiates on sits outside the certified scope, which is why business structure is the thing worth reading.

Where SST sits inside each company’s business

Every row comes from the company’s own published materials, fetched or re-fetched on August 19, 2026. The table describes where SST sits. It does not rank the six.

Table: each certified provider’s customer segment and business scope as this site reads their published materials, and where SST sits inside it. Checked August 19, 2026.

Provider	Who it publishes for	The company’s published scope	Where SST sits
TaxCloud	Mid-market ecommerce and SaaS brands, five or more states of nexus	United States sales and use tax, plus Canada. No VAT, e-invoicing, or excise product published	A single-market business. SST is a named item in the Products menu
AccurateTax	Small business ecommerce	United States small business ecommerce sales tax, sold around shopping carts	A single-market business. On the homepage in a content module, not in the navigation
Avalara	Not published. The two tiers it prices are gated by annual revenue, and a larger business is routed to a custom quote instead	190+ countries. Sales and use, VAT, e-invoicing, excise, communications, occupancy, property, business licenses, 1099 and W-9, cross-border	One program among many. An SST item appears in the Products mega menu, and there is a separately named, publicly priced SST tier
Sovos	Ecommerce and other remote sellers, on its own SST page. No minimum or maximum customer size stated	Global compliance. e-invoicing, tax determination, filing and reporting, 1099, withholding, ACA, unclaimed property, insurance and beverage alcohol specialties	One program among many. The SST Model 1 page is live and was not reachable from homepage navigation on the fetch date
Avior	US distributors and retailers, on its own corporate site	Excise verticals alongside sales tax: tobacco and vapor, motor fuel, beverage alcohol, MSA and scan data. Sales and use tax is one of five lines	One line among five. SST content sits on the suttax.avior.tax subdomain
Exactor	Not published	Absorbed into QuickBooks Online. The Governing Board routes contact to Intuit	Certified, and listed by the Board as not currently offering free services under the CSP program

What the site-structure observations are worth

Three site-structure facts sit in that table. Each one records where a link sat on August 19, 2026, and nothing more.

• The words Streamlined and SST didn’t appear on the Sovos homepage or in its navigation as fetched, and the SST Model 1 page wasn’t reachable from that navigation.
• The words Streamlined and Certified Service Provider didn’t appear on avior.tax or in its navigation as fetched. Its Sales Tax item links to a separate subdomain, where the SST page lives.
• AccurateTax carried SST on its homepage in a content module rather than in the navigation.

What these facts are not. They aren’t evidence of intent, commitment, investment, or service quality, and this page doesn’t read them that way. Sites get reorganized, and an SST page you reach by search is still a live SST page.

One more observation closes off a tempting argument. As fetched on the same date, both Avalara and TaxCloud surface an SST item inside their Products mega menu, and neither carries SST as a standalone top-level label. Avalara also publishes a separately named tier, Core Compliance + SST Services, at a published price. No ranking of the six on how prominently they market SST survives inspection, which is why this page does not attempt one. A menu-depth argument isn’t defensible in either direction, so you won’t find one here.

What changes when SST is the core business

Sell one market and one tax type and a few things follow from arithmetic rather than from marketing.

The program is a larger share of the roadmap. A vendor whose entire product is United States sales tax has no VAT mandate somewhere else competing for its engineering time. That’s a statement about where attention can go, not proof of where it went.

The commercial model has to work inside the program. A single-market vendor prices around the program rather than beside it. AccurateTax prices by order volume, with filing and certificate management as add-ons, and publishes the shape without the number. TaxCloud prices the same way and does publish the numbers, on two plans a buyer needs together.

And the ceiling is real. A single-market vendor stops where its market stops. If your obligations grow past US sales tax, you’re running a second vendor or switching providers, and switching has a cost in data, mappings, and filing continuity.

The case for choosing a provider where SST is one program among many

This is the half of the argument that usually gets left out, and most of the points below are about the part of your footprint the program never touches.

1. Most of your cost and risk sits outside the program. Free CSP services apply in the full member states where you qualify. Everything else is priced normally: the non-member states, the states where you don’t meet all five criteria, and home rule jurisdictions. Avalara puts it plainly: “For non-SST states and non-volunteer sellers, standard pricing and per-return fees apply.” If two thirds of your footprint sits outside the program, you’re mostly buying the non-SST product.

2. ERP depth is published, and it’s concentrated in the broad vendors. Sovos publishes standard adaptors for SAP, Oracle NetSuite, Microsoft Dynamics, Magento, QuickBooks Online, and Shopify, plus an ERP and procurement connector marketplace. Avalara reports 1,400 plus signed partner integrations, naming NetSuite, SAP, Oracle, Microsoft Dynamics, and Salesforce. Neither AccurateTax nor TaxCloud publishes an SAP or Microsoft Dynamics connector. If your revenue runs through a large ERP, that gap decides your shortlist before SST ever comes up.

3. Published support terms are more detailed at the larger vendors. Avalara publishes three support tiers with stated hours and response targets. Avior publishes no support commitment of any kind, and AccurateTax publishes channels without a response target. That’s a documentation contrast rather than a quality measurement, and if your procurement scores published service levels, it settles the question.

4. A published price is worth something. Avalara publishes tier pricing on its own pricing page, checked August 19, 2026, and it’s the broadest platform of the six as well. TaxCloud publishes its two plans in full, checked September 1, 2026. So if you have to model a cost before you take a sales call, those are numbers you can model with. Three publish nothing. See what each certified provider charges.

5. Growth beyond the program is normal. VAT registration, an e-invoicing mandate, excise obligations on tobacco, fuel, or alcohol, business licenses, 1099 reporting: each of those arrives from the business, not from the tax team. Sovos and Avalara sell all of them, and Avior sells the excise lines. Buying breadth you don’t need yet is a real cost. So is re-running a vendor selection in eighteen months.

6. Vendor consolidation has its own value. One contract, one security review, one data processing agreement, and one integration is a smaller operating burden than three.

The honest summary of this section: if your obligations are US sales tax, your footprint sits heavily in member states where you qualify, and you’re on mainstream carts, narrow scope is a reasonable filter. If you run a large ERP, expect international obligations, or have most of your footprint outside the program, breadth is the stronger filter and SST centrality is close to irrelevant. Either way, shortlist on the non-SST product, because that’s the part the states don’t fund. The same questions are answered for every provider in the six certified provider profiles.

What this page cannot tell you

Business-model centrality is not evidence of service quality. This page shows where SST sits inside each company’s published scope. It cannot tell you which provider files more accurately, answers a notice faster, or handles an audit better. Nothing on this site measures those things, no public source measures them consistently across all six, and structural position is not a proxy for any of them. A provider with SST at the center of its business can serve you badly, and a provider with SST as one program among dozens can serve you well.

Two further limits. Every site-structure statement here describes one date, August 19, 2026. And none of the six publishes the share of revenue or customers attributable to SST, so core business here means published product scope, which is a proxy and not a financial one.

Frequently asked questions

Is any certified provider SST-only?

No. As of August 19, 2026 none of the six sells SST as its only product. The closest structural position is a company whose entire scope is United States sales and use tax, where SST is one part of a single-market business.

Does a provider focused on SST deliver better certified services?

There’s no published basis for saying so. The certified free services list, the certification standard, and the compensation rule are set by the Governing Board and apply identically to all six.

If the certified services are the same, what am I choosing between?

Everything outside the certified scope: coverage in non-member states, integrations, exemption certificate handling, registration services, support terms, price, and how the vendor behaves when a state sends you a notice. That’s where the six genuinely differ. A hard-to-find SST page matters only in that it makes a provider harder to research.

Sources and last checked

Last checked August 19, 2026. Built only from Governing Board pages and each company’s own public materials, with every site-structure observation re-verified on that date rather than carried over. Extracts cached with their fetch dates.

• The Governing Board’s certified service provider list, which is where the roster of six and each provider’s free-services status come from
• Provider homepages, SST pages, and pricing pages, all cached with their fetch dates

Pages change. Confirm current scope with each provider, and see what a Certified Service Provider is for the program baseline.